Thyroid Flashcards
What is the shape of the thyroid?
Butterfly shape
Where is the thyroid located?
Based of the neck
How many lobes of they thyroid are there?
2 lobes (LT and RT)
Is the thyroid encapsulated?
Yes
Thyroid cartilage is related to which ring?
5th/ 6th ring
The thyroid can sometimes be a _________ __________: which is what?
- Pyramid lobe
- Fetal remnant, extends cranial from isthmus
What is the size and shape of the thyroid?
Variable but
1. Length: 4-6
2. AP: 2CM most precedes
3. Width 2 cm
4. Isthmus: 2-6 mm
Label the image
Label the structures
How vascular is the thyroid?
Very
What supply’s the RT and LT superior thyroid arteries?
ECA
What supplies blood to the RT and LT inferior thyroid arteries?
Subclavian artery branch
What are the three veins of the thyroid?
- Superior
- Middle
- Inferior
What is the lymph drainage for the thyroid?
Deep cervical nodes around carotids
What is the most common site for thyroid CA to metastasize?
Cervical nodes around carotids
What is the sonographic appearance of the thyroid? 3
- Homogenous
- Medium level echoes
- Hyper echoic thin capsules
What does this image demonstrate?
The esophagus
Label the image
- Colloid in lumen of follicle
- Parafollicular “C” cell
- Follicular cell
- Follicle
What kind of gland is the thyroid gland?
Endocrine gland
What does the thyroid do? What does it produce? 3
- Synthesize, stores, secretes hormones
- Regulates body metabolism
- Produces T3, T4, and calcitonin
What does T3 and T4 do?
Affect metabolic rate
What chemical helps synthesize T3 and T3?
Iodine
What does Calcitonin do?
Maintains homeostasis of blood calcium
How does calcitonin do what it needs to do? What does it act on?
- Decrease concentration of blood calcium
- Acts on bone > inhibits breakdown
What thyroid hormone does the hypothalamus release?
TRH
What thyroid hormone does the pituitary gland release?
TSH
How does the hypothalamus affects the pituitary gland?
When there is low blood levels of thyroid hormones the Hypothalamus releases TRH to pituitary so that it can release TSH to the thyroid follicle
What can affect thyroid hormone levels in blood?
Thyroid disease
What are three kinds of thyroid diseases or states?
- Euthyroid
- Hypothyroid
- Hyperthyroid
What is hypothyroidism?
- Under secretion of thyroid hormones
- Body metabolism decreases
What is hypothyroidism related to? 3 (what causes it)
- Low intake of iodine
- Dysfunction of gland
- Pituitary gland abnormality
What are some signs/ symptoms of hypothyroidism? 5
- Weight gain
- Hair loss
- Lethargy
- Cold intolerance
- Husky voice
What are some causes of hypothyroidism? 4
- Hashimoto’s - most common in N.A
- Iodine deficiency - worldwide
- Partial thyroid echo my
- Pituitary gland problems
What is hyperthyroidism?
- Overproduction of thyroid hormones
- Body metabolism increases
What is hyperthyroidism related to? 2
- Entire thyroid gland over functioning
- Neoplasm
What are some signs/ symptoms of hyperthyrodism? 6
- Weight loss, increased appetite
- Nervousness
- Sweating, heat intolerance
- Palpitation
- Fatigue
- Exophtalmos
What are some causes of hyperthyrdism? 5
- Graves’ disease (with a goiter)
- Toxic adenomas
- Inflammation of thyroid
- Excessive thyroid medication
- Pituitary tumour
What are some lab tests for thyroids? 4
- T3
- T4
- TSH
- Thyroid antibodies (autoimmune disorders)
What is/are other tests we do besides the hormone thyroid tests? What does it determine? How is it given? What do the two results mean?
Nuc med
1. Determines function
2. Radioisotope given to patient
3. Hot nodules > hyper functioning > Benign
4. Cold nodules > Non functioning > possible malignancy
What are some indications for thyroid scans? 4
- Increase in gland size (symmetric or asymmetric)
- Change in metabolism
- Nuclear medical scan - Cold nodule
- Palpable lump
How do we prepare to scan the thyroid? 5
- Obtain patient history
- Place patient in a supine position
- Elevate the shoulders slightly
- Neck minimally hyperextended
- Physical assessment
What do we do for a physical assessment when preparing for a thyroid scan for palpable masses?
- Request that the patient localize the palpable mass
- Once located, request permission to touch the patient and palpate the mass
- If consent is given, Palpate the region of interest
What kind of probe do we use for a thyroid scan?
High frequency linear probe
What are some benign focal diseases in the thyroid? 3
- Cysts
- Thyroglossal duct cysts
- Adenoma
How common are true cysts in the thyroid?
Uncommon
Commonly ____ ________ of a follocular adenoma is seen in the thyroid
- Cystic degeneration
When would we have hemorrhagic cysts in the thyroid? And what are they?
- When we receive blunt trauma to neck
- Acute hemorrhage of adenoma
What is the sonographic appearance of a simple cyst?
Anechoic
What is the sonographic appearance of a complex cyst?
- Internal Echoes
- Irregular wall
What is the sonographic appearance of a colloid cyst?
Echogenic focci with comet tail
What does this image demonstrate?
Colloid cyst
What kind of abnormality is a thyroglossal duct cyst?
Congenital abnormality
Where is thyroglossal duct found? 2
- Midline of neck
- Anterior to trachea
What is a thyroglossal duct cyst?
Failure of tract to atrophy (base of tongue to isthmus)
What kind of structure is a thyroglossal duct cyst? How big is it?
- Fusiform cystic structure
- less than 3cm
What is this an image of?
Thyroglossal duct cyst
Which demographic is more likely to develop an adenoma?
Women > Men
Is adenoma something to worry about?
They are generally benign
What is the most common type of adenoma?
Follicular adenoma
With Nuclear Medicine test how does adenoma’s present?
- Asymptomatic
- Typically cold nodule
How fast do adenoma’s grow?
They are slow growing and variable in size
What is the sonographic appearance of a adenoma? 6
- Anechoic > ISO > Hyper
- Solitary
- Defined
- Round/ Oval
- Hypoechoic halo
- Eggshell calcification
What does this image demonstrate?
Adenoma
What are some benign diffuse disease? How do we determine these? 3
- Inflammation (Thyroiditis)
- Hyperplasia (Goiter)
- Diagnosis based on clinical and lab findings
What is thyroiditis? and who is most likely affected
- Inflammation and fever
- Swelling and tenderness of the gland
- Middle- aged women
What diseases are related to thyroiditis? 5
- Hashimoto’s
- Acute suppurative
- Subacute granulomatous
- Silent
- Invasive fibrous (Reidel’s)
What is Hashimoto’s disease? What kind of disease is it? How painful is it? What kind of antibodies is seen with it? 4
- Chronic lymphocytic inflammation disease
- Autoimmune
- Typically painless
- Antithyroid antibodies
What is the most common form of Hashimoto’s?
Adult hypothyroidism
If one has Hashimoto’s they have an increased risk of what condition?
Lymphoma
Which demographic is typical affected with Hashimoto’s ?
Women
What does Hashimoto’s look like sonographically? 7
- Diffusely enlarged
- Heterogeneous
- Hypoechoic
- Possible discrete nodules or calcifications
- Difficult to differentiate from MNG
- May be hyper vascular (acute stages), but vascularity typically normal or decreased
- Cervical lymphadenopathy
What does this image demonstrate?
Hashimoto’s
What is acute suppurative thyroiditis? What is it typically caused by?
- Firm painful thyroid
- Bacterial infection
What are some signs for acute supportive thyroiditis?2
- Low grade fever
- Sore throat
How common is acute suppurative thyroiditis? Who is the most common demographic impacted?
Children
What does this image demonstrate?
Acute suppurative thyroiditis, Note the
- Enlargement
- Hypoechoic
- Possible abscess
What is silent thyroiditis?
Enlarged gland with no pain
What does silent thyroiditis resemble?2
- Hashimoto’s
- Clinically: Subacute granulomatous
What is invasive fibrous (Riedel’s struma)? What does it look like? How can it affect the extra thyroid?
- Typically complete destruction of gland
- Enlarged heterogeneous thyroid
- Inflammatory process can extend extra thyroid
What is the rarest form of thyroiditis?
Invasive fibrous (Riedel’s Struma)
What is hyperplasia? 4 (of the thyroid)
- Goiter
- Diffuse enlargement of the thyroid
- Palpable gland
- +/- functional disturbance
What are some causes for hyperplasia? 2
- Iodine deficiency
- Defect in normal hormone synthesis
How long does it take for hyperplasia to manifest?
typically years to manifest
What are some disease that are related to hyperplasia? 3
- Graves disease
- Nontoxic goiter
- Multinodular goiter
What is graves disease?2
- Autoimmune disorder
- Diffuse toxic goiter
What are some signs and symptoms of Grave’s disease? 4
- Hyperthyroidism
- Exophthalmos
- Skin thickening
- Clubbed toes and fingers
Which demographic is generally affected by Grave’s disease?
- Women > Men
- 30 - 40 years of age
What does graves disease look like sonographically?5
- Diffuse symmetrical enlargement
- Lobulated
- Homogenous or heterogeneous
- Hypoechoic
- “Thyroid inferno”
What does this image demonstrate?
Grave’s disease
What is a non-toxic goiter?
- Endemic or sporadic goiter
- No functional disturbances
What causes a non-toxic goiter?
Lack of iodine in diet
How fast does non-toxic goiters grow?
Slow
What does non-toxic goiters look like on ultrasound?
- Diffusely and uniformly enlarged
- Smooth or nodular echotexture
- Typically not as large as MN goiters
What is a Multinodular goiter?
Adenomatous goiter
What causes multi-nodular goiters?
Due to iodine deficiency > deficiency of thyroid hormone production > TSH from pituitary stimulates thyroid > Thyroid enlargement
Which demographic of individuals is most likely affected by Multinodular goiters?
Females aged 50-70
What does Multinodular goiters look like sonographically? 4
- Enlarged often asymmetrical
- Diffusely heterogenous
- Multiple discrete nodule
- Calcifications
- Cystic areas
What does this image demonstrate?
Multinodular Goiter
What are malignant lesions?
Solitary nodules more worrisome than multiple
What is the common demographic affected with malignant lesions?
- Women > Men
- 40-60 years old
How fast does malignant lesions grow?
Slow
Was is needed for analysis for Malignant lesions?
FNA needed for diagnosis; no sonographic feature is sensitive or specific enough
How does the patient present with Malignant lesions? 3
- Pressure symptoms (difficulty breathing or swallowing)
- Painless, palpable neck mass
- Hoarseness
What is the sonographic appearance of malignant lesions? 8
- Variable appearance
- Often Hypoechoic
- Poorly defined boarders
- Jagged boarders
- Absence of halo
- Microcalcifications
- Taller than wide
- Enlarged nodes
What are some thyroid cancers? 6
- Papillary
- Follicular
- Medullary
- Anaplastic
- Lymphoma
- Metastases
Are papillary carcinomas asymptomatic or symptomatic? How fast do they grow?
- Asymptomatic
- Slow growing, may spread to cervical lymph nodes
Which demographic of individuals are affected by papillary carcinoma?
Females > males
Which is the most common/ least aggressive thyroid cancer?
Papillary carcinoma by 60- 70%
What does this image demonstrate?
Papillary Cancer, note the
- Solid
- Hypoechoic
- Microcalcifications
- Tiny to 10 cm
- Hypervascularity
Follicular carcinomas grow how fast and how aggressive are they compared to papillary? Do they metastasize from somewhere? If they do where from?
- Slow growing but more aggressive than papillary carcinoma
- Metastases to lung and bone via blood
What are the occurrence rate follicular carcinoma?
15- 20%
What is the demographic of individuals affected by follicular carcinoma?
- Female > males
- 40-50 years
What increases the risk of follicular carcinoma?
history of radiation to thyroid risk factor
What does follicular carcinoma look like sonographically? 5
- Appearance of an adenoma
- Enlarging encapsulated nodule
- Irregular boarders
- Thick halo
- Microcalcifications
What is the demographic of individuals that are affect by Medullary carcinoma?
Men and women equally
What is medullary carcinoma?
- Hard bulky mass
- Metastasize readily
What does the medullary carcinoma secrete?
Calcitonin
How many cases are related to medullary carcinomas?
5%
What does medullary carcinomas look like sonographically? 5
- Solid
- Hypoechoic
- Well-circumscribed
- Encapsulated
- Coarse Calcifications
What is anaplastic carcinoma? Patients are at risk of what?
- Aggressive invasion of adjacent structures
- Death by compression/ Asphyxiation
What is the most rarest and most aggressive carcinoma?
Anaplastic carcinoma
Who is most affected by anaplastic carcinoma?
Common in older patients >60 years
What does anaplastic carcinoma look like sonographically? 4
- Hypoechoic, solid
- Irregular
- Encase or invade blood vessels
- Invade neck muscles
What is Lymphoma?
- Rapidly growing mass
- Hypoechoic, lobular, non vascular
- Most non- Hodgkins
Which demographic of individuals are affected by Lymphoma? What do they have a history of typically? What is the most common variation?
- Most non- hodgkin’s
- Older females
- History of hashimotos
What is matastases frequency? What is the route? Which tissues? 3
- Infrequent
- Hematogenous route
- From breast, lung, colon, melanoma
About _____ % of patients with systemic lymphoma have ______ __________.
- 20%
- Thyroid involvement
Label the structures
What is the criteria for a benign thyroid lesion? 5
- Regular, well defined borders
- Thin, Hypoechoic halo
- Solitary or multiple minute cysts within mass
- Hyperechoic
- Large calcifications, especially around the periphery
What is the criteria for a malignant thyroid lesion? 3
- Irregular border
- Absence of a halo
- Macrocalcifications